New research

US emissions increase hints at limitations of Obama’s clean power plan

  • 22 Oct 2014, 17:10
  • Mat Hope

US energy sector emissions increased slightly in 2013, according to new data from the Energy Information Administration (EIA). This may seem like bad news for President Obama, who has pledged to cut the country's emissions 17 per cent by 2020.

Obama unveiled his  clean power plan earlier this year to much fanfare. The centrepiece of the plan is to reduce emissions from electricity generation by 30 per cent by 2020.

The US's rising energy sector emissions seem to  suggest the policy may not be as effective as Obama hopes.

Obama's clean power plan specifically targets emissions from power generation, which accounts for   about 32 per cent of the US's total emissions. Cutting emissions from the US's homes and businesses is a much smaller part of his wider   Climate Action Plan.

The EIA's data shows the potential limitations of focusing on cutting power generation emissions without addressing the country's broader energy consumption.

Emissions increase

US energy sector emissions increased 2.5 per cent in 2013 compared to year before, the EIA's data shows. The EIA says the main reason for the increase was colder weather.

Winter temperatures at the start of 2013 were lower than a year before, and the US also experienced a particularly mild spring last year. Temperatures fell again later in the year, when the US was  engulfed by the polar vortex.

Screen Shot 2014-10-22 at 16.15.40.png
Source: National Oceanic and Atmospheric Administration, average monthly temperatures. Graph by Carbon Brief.

Households and businesses turned up their thermostats in response to the lower temperatures, which meant burning a lot more gas and a bit more oil. The residential sector was responsible for 48 per cent of 2013's emissions increase, mostly due to heat demand, the EIA says.

more

Factcheck: Will climate change lead to giant, man-eating snakes, tiny horses and shrunken goats?

  • 22 Oct 2014, 14:01
  • Robert McSweeney

Rising temperatures have caused mountain goats in the Alps to 'shrink' by up to 25 per cent, according to new research . The news follows on from recent stories of how climate change could bring us huge spiders, tiny horses and giant snakes.

Despite the slightly ridiculous headlines such research prompts, there is actually some science behind it all.

Behavioural change

So, first things first; rising temperatures haven't actually caused any goats to shrink per se. Rather the research, published in the journal Frontiers in Zoology, finds that young goats aren't as big as they were 30 years ago.

Scientists analysed records of the Alpine Chamois goat in the Italian Alps and found they were as much as 25 per cent smaller than goats of the same age in the 1980s.

more

Worst case scenarios of sea level rise, and why scientists and policymakers consider them

  • 21 Oct 2014, 17:52
  • Robert McSweeney

Sea levels could rise by a maximum of 190 centimetres by the end of the century, according to a new study, which examines a worst case scenario for sea level rise.

In reality, the amount of sea level rise we get is likely to be less than that. But scientists and policymakers examine such 'worst case' scenarios to safeguard against climate risks.

Upper limit

With 10 per cent of the world's population living less than 10 metres above sea level, the threat of  coastal flooding is significant. The Intergovernmental Panel on Climate Change (IPCC) expects sea level rise to cause a ' significant increase' in sea levels extremes and the risk of coastal flooding.

The new study, published in  Environmental Research Letters, considers the assessment of 13 ice sheet experts. They conclude that the contribution from ice sheets is likely to be greater than projected by the IPCC. The paper suggests that sea levels could rise by as much as 190 cm this century.

Projections of sea level rise are typically constructed by working out the contribution to sea level rise from different  factors. The biggest contribution is from water expanding as it warms, followed by melting glaciers, then melting ice sheets on Greenland and Antarctica.

The crucial question for sea level rise this century is how much ice will be lost from the ice sheets, the authors argue. But it remains one of the largest uncertainties. In its Fifth Assessment Report (AR5), the IPCC says there isn't sufficient evidence for them to give probabilities of large-scale losses of ice sheets.

The new study uses expert judgement to consider areas of ice sheet loss that are often not included in the sea level  models that the IPCC bases its assessment on. They then combine these judgements with the methods used in AR5 to produce their upper-limit figure of 190 cm.

more